Support for mocha's aliases

[apellerano-pw]

Anything that operates on describe() should operate on context(); operates on it() should also operate on specify()

from https://mochajs.org/#bdd

context() is just an alias for describe(), and behaves the same way; it just provides a way to keep tests easier to read and organized. Similarly, specify() is an alias for it().

It goes on to list further aliases if you're using mocha with a TDD or QUnit-like syntax, but I don't personally use those or know if they're endorsed in the ember community so I'm not sure exactly how they should be included.